The invention relates to a method and an apparatus for start-up control on motor vehicles.
Start-up control systems of the prior art are intended to prevent an uncontrolled slipping of the drive wheels when movement of the vehicle is started on a smooth surface (DE-PS No. 18 08 799). Such slipping unnecessarily prolongs the time required to accelerate the vehicle to running speed and reduces its traction, as well as lateral stability.
The slipping of the drive wheels is measured by rotation sensors located on the wheels and is evaluated in an electronic system. If only one wheel is slipping, the corresponding wheel brake is activated, e.g., via a valve (differential brakes). A drive torque is thereby transmitted via the wheel differential to the other stopped wheel.
However, if both wheels are slipping, the power of the engine is adjusted downward. For this purpose, an intervention in the carburetor throttle control must be made, and the value set by the driver must be reduced. This occurs, for example, by means of interposed electrical solenoid actuators or a pneumatic or hydraulic work cylinder.
With the configuration described above, the gas is taken away from the engine as soon as one wheel on the drive axle starts to slip. This is recognized by the occurrence of a +b control signal (acceleration signal of one wheel). Then, as soon as the +b signal has disappeared, the gas setting desired by the driver is re-established.
Such a control concept (black-white control) naturally causes a relatively uncomfortable acceleration of the vehicle.
The object of the invention, therefore, is to provide a system by means of which the vehicle start-up operation can be executed without passenger discomfort. A pre-requisite, however, is that, as in the prior art, there is only one black-white signal present to indicate the slipping of the drive wheels.